Sweet science: Genome project targets chocolate

Humans have been getting pleasurable hits from chocolate for more than 2,000 years, and now, for the first time, not one but two scientific collaborations have decoded the genetic sequence for the plant that gives rise to the blissful stuff. Why? What could possibly improve chocolate? Plenty, said Mark Guiltinan, a plant molecular biologist at Pennsylvania State University and leader of one of the rival efforts.

Chocolate, he said, originates in the poorest countries of the world, mostly from small farmers in the tropics. The cacao plants that produce the cherished cocoa beans are vulnerable to disease and drought - much of Brazil's cacao was recently destroyed by a fungus, for example.

The scientists said the main aim of the projects wasn't to bring the world genetically modified candy bars. Having the sequence of genetic code will allow them to improve and accelerate selective breeding, said Guiltinan, with the goal of growing plants that yield more cocoa beans and resist drought and disease.

Genetic sequencing has already improved breeding for corn, soybeans, and other major crops, he said.

Will any of this lead to a better-tasting chocolate? It's possible, but the flavor comes not from the growing but from a process of fermentation. Typically that happens on sidewalks and farms in Africa or South America, where the beans are left to be attacked by bacteria yeasts and molds.

That breaks down the starches and proteins in the beans, creating lots of smaller compounds that, after roasting, make chocolate taste chocolaty. Chemical analyses have shown that chocolate can contain the same compounds that impart flavor and scents to fruits, flowers, sherry, vinegar, butter, almonds, caramel, nutmeg, and other spices - and, in some cases, Swiss and blue cheese.

Guiltinan said his chocolate genome project started in the late 1990s when he and other scientists got grant money from a consortium of chocolate companies, including Hershey. But around the same time, Mars Inc. and the Agriculture Department together decided to launch their own genome project.

Luckily, the two went after different varieties of the cacao plant. The Mars people sequenced a cutting from a variety called Forastero, which they say is the progenitor of most chocolate on the market today.

The other group chose a sample of an heirloom variety called Criollo, which Guiltinan said is closely related to the original chocolate that the Mayans and Aztecs consumed as a hot drink laced with peppers.

The Mars people put their genome online last month, a seeming victory in the race. But Guiltinan said his group, which includes researchers from 18 institutions, was waiting to have its chocolate genome published in a peer-reviewed journal so it could be vetted for scientific soundness and accuracy.

In response to the Mars announcement, the group got its results released before publication.

Howard-Yana Shapiro, a botanist for Mars Inc., said that group didn't want to wait to make its sequence public because so many breeders and growers were clamoring for it.

If there's any real race between the two groups, it's more over credit than money. Neither is filing for patents, and both sequences are public and free for anyone who wants to use them.

Even if it won't enhance the taste of s'mores.

- Faye Flam